Treatment of animal litter with ferric sulfate granules

ABSTRACT

Methods of treating animal litter and/or bedding material for control of volatile ammonia and soluble phosphorous include applying granular partially hydrated ferric sulfate to the litter. The partially hydrated ferric sulfate ranges from gray to tan in color and is spread onto the litter at a rate effective to reduce ammonia volatilization and reduce soluble phosphorous. Relative to reagent grade ferric sulfate, the partially hydrated ferric sulfate exhibits lower hygroscopicity and higher deliquescence. The ferric sulfate is prepared by a process comprising oxidizing ferrous sulfate with sulfuric acid using a molecular oxygen oxidizing agent at an elevated pressure relative to atmospheric and at a temperature of 60° C. to 140° C. to produce a gray to tan colored granular product.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. UtilityApplication entitled, “Treatment of Animal Litter With Ferric SulfateGranules” having Ser. No. 12/018,499, filed Jan. 23, 2008, which claimspriority to U.S. Provisional Application No. 60/881,887, filed Jan. 23,2007, all of which are hereby incorporated by reference.

BACKGROUND OF INVENTION

This disclosure generally relates to the use of iron salts to lowerammonia emissions and sequester soluble phosphorous in animal litter orbedding materials, and more particularly, to the use of a ferric sulfatecomposition applied as a granular solid to the animal litter.

Ammonia is a common by-product of animal waste due to the ofteninefficient conversion of feed nitrogen into animal product. Livestockand poultry are often fed high-protein feed, which contains surplusnitrogen, to ensure that the animals' nutritional requirements are met.Nitrogen that is not metabolized into animal protein (i.e., milk, meat,or eggs) is excreted in the urine and feces of livestock where furthermicrobial action releases ammonia into the air during manuredecomposition. Because of this, in-house air quality is a major concern.Producers spend much of their time and investment in maintaining goodair quality to maximize growth and performance of livestock. Ammonialevels of 25 ppm or more can lead to significant health problems for theanimals including respiratory infections and eye lesions, or even deathof the animal. For example, previous work has correlated negative birdperformance with poor indoor air quality in poultry growing and holdingareas due to ammonia (NH₃) and dusts. Low growth rates, low feedutilization rates, high mortality rates, costs of house ventilationespecially in the cooler months are all losses that can be related tothe quantities of ammonia and ammonia compounds generated by livestock.As used herein, the term “livestock” is intended to refer to poultry,swine, cattle, horses, and like animals that are generally containedwithin a confined area for extended periods of time.

Ammonia is a colorless, alkaline, water-soluble gas that is produced bymicrobiological deamination or reduction of nitrogenous substances.Animal litter, a combination of fecal material, spilled feed, beddingmaterial, and the like, provides a source of ammonia emissions withinfloor-reared production facilities. For example, birds excrete excessnitrogen (N) in the form of uric acid and it is the microbialdecomposition of uric acid within the litter, which is the primarysource of ammonia generation. Litter type, management, humidity, pH, andtemperature all affect ammonia generation and concentration. Ammoniavolatilization is a complex physical and chemical process and emissionsare generally related to four factors: ammonium ion concentration of themedium, temperature of the medium, pH of the medium and turbulenttransport of the ammonia from the medium. There is a trend within theindustry for tighter house design and less frequent litter or beddingmaterial removal. These two factors have the potential to dramaticallyincrease the ammonia concentration within production facilities.

With respect to poultry houses, commercial poultry producers generallyemploy some form of ventilation to mitigate volatile ammoniaconcentrations emanating from decomposing animal litter in their houses.Current ventilation methods consume energy both for air exchange and forheating makeup air.

Animals are also susceptible to ingestion of materials used in litterand/or bedding material treatments. A typical material used is alum,i.e., aluminum sulfate. Application of urease inhibitors to cattleand/or swine manure has effectively limited urea hydrolysis inlaboratory and field studies. Such inhibitors are easily degradable andmust be continuously applied to manure in order to reduce the productionof ammonia from urea. Still other litter amendment materials includeferrous sulfate, liquid ferric sulfate or chloride, and the like. InU.S. Patent Application No. 2006/0005784 A1, the use of the liquidferric sulfate or chloride is described as an advantage over granularreagent grade ferric sulfate crystals because the animals can ingest thegranular form of ferric sulfate crystals and the use of the solid formto be distributed in practical quantities is reported to be marginallyeffective. The ferric sulfate crystals, whether they be technical orreagent grade, have a yellowish to white color that is generallydistinguishable from the litter and common materials used in the housesuch that it can be visible to the animals, which leads to accidentalingestion since the animals can confuse the litter amendment with feed.

In addition to the production and welfare impacts, there is growingpublic concern over outdoor air quality and the amount of pollutantsreleased by animal feeding operations (AFOs). Of greatest interest arethe emissions of ammonia and particulate matter. Environmental air andwater quality potentially can be impacted by animal production emissionsin the form of atmospheric nitrogen deposition. Since these emissionsoriginate from within the production facilities, strategies to reducethe generation of dust, ammonia, and odors within houses will have acorresponding impact on the level of house emissions.

One technique to reduce emissions from production facilities, such aspoultry production barns, lowers the pH of the litter to maximizeconversion of volatile ammonia to ammonium ion (NH₄ ⁺). Application oflitter treatments to reduce the pH of the litter is the mechanism usedto accomplish the pH reduction. Typical acidifier litter treatments suchas alum are effective for short-term ammonia reduction, up toapproximately two weeks. Amounts required for longer-term effectivenessin chemically binding litter nitrogen are corrosive, representadditional hazards to the animals, and are difficult to apply with theanimals present in the production facility.

Soluble litter phosphorous (P) in the form of phosphates (PO₄ ⁻²) isanother concern when land-applied to lands already overburdened withphosphates and susceptible to surface water runoff and edge of fielderosion. Products that can bind soluble phosphorous in land-appliedanimal litter and/or bedding material would benefit the industry inaddressing water quality impacts from these various operations.

In view of the foregoing, there accordingly remains a continued need inthe industry to more efficiently address the problems associated withvolatile ammonia emissions and soluble phosphorous in animal litterand/or bedding materials.

BRIEF SUMMARY

The above-described concerns and disadvantages are addressed using aform of ferric sulfate that is formulated to be a granular solid, hasminimal dust component, exhibits excellent storage stability, andpossesses relatively low hygroscopic properties for ease in handling andstorage while rapidly deliquescing when applied to animal litter and/orbedding material. In one embodiment, a method of treating animal litterand/or bedding material for control of volatile ammonia and solublephosphorous comprises applying a granular form of a partially hydratedferric sulfate composition to the animal litter at a coverage rateeffective to reduce ammonia emissions and reduce soluble phosphorouslevels, wherein the ferric sulfate is prepared by a process comprisingoxidizing ferrous sulfate with sulfuric acid using a molecular oxygenoxidizing agent at an elevated pressure relative to atmospheric and at atemperature of 60° C. to 140° C. to produce a slurry, and drying theslurry to produce a gray to tan colored granular product gray to tancolored granular product.

In another embodiment, a method of treating animal litter and/or beddingmaterial for control of volatile ammonia and soluble phosphorouscomprises applying a granular form of a partially hydrated ferricsulfate composition to the animal litter and/or bedding material at acoverage rate effective to reduce ammonia emissions and reduce solublephosphorous levels, wherein the ferric sulfate has a substantiallykornelite crystalline structure.

The above discussed and other features and advantages of the presentdisclosure will be appreciated and understood by those skilled in theart from the following detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the figures, which are exemplary embodiments andwherein like elements are numbered alike:

FIG. 1 graphically illustrates ammonia concentrations estimated usingdosimeter tubes and litter moisture content in the Comp-1 (Houses 1 and2) and Inv-1 (Houses 3 and 4) houses. Averages are the means of Comp-1and Inv-1 houses.

FIG. 2 graphically illustrates ammonia concentrations normalized withrespect to ventilation rates in Comp-1 and Inv-1 houses compared tohouse air temperature, percent litter moisture, and fan-flow periods perday.

FIG. 3 graphically illustrates litter analysis of Comp-1 and Inv-1litters.

FIG. 4 graphically illustrates litter analysis of Comp-1 and Inv-1litters.

FIG. 5 graphically illustrates litter analysis of Comp-1 and Inv-1litters.

DETAILED DESCRIPTION

Disclosed herein are processes for treating animal litter and/or beddingmaterial that inhibit ammonia volatilization and reduce solublephosphorous levels in the litters, among other benefits. The processesare suitable for various animal litter and/or bedding materialsincluding, but not limited to, those associated with dairy cattle ad/orcalves, swine, equine, poultry, and the like. The processes generallyinclude application of a granular form of a ferric sulfate compositionto the animal litter and/or bedding material. The ferric sulfatecomposition is prepared by a process that results in a product that is agray to tan colored, possesses relatively low hygroscopic properties yetdeliquesces rapidly after application, effectively inhibits ammoniavolatilization, and effectively reduces soluble phosphorous levels aswill be discussed in greater detail below. Relative to reagent ortechnical grade ferric sulfate crystals, which are generally yellow towhite in color, Applicants have unexpectedly discovered that the gray totan colored ferric sulfate composition is indistinguishable from thelitter and/or bedding materials commonly used in the animal productionfacilities, thereby lowering inadvertent ingestion of ferric sulfate bythe animals since it has been discovered that the yellow to whitecolored technical or reagent grade ferric sulfate product when appliedas a granular solid can be distinguishable and can be confused as a foodproduct and accidentally ingested. Ingestion of litter amendment canaffect productivity. This is especially advantageous as it relates topoultry since it has been qualitatively observed that the birds do notassociate the granular form of the so-colored ferric sulfate as feedmaterial.

In addition to the color differences, Applicant has unexpectedlydiscovered that its ferric sulfate composition is partially hydrated anddeliquesces faster than technical or reagent grade ferric sulfate. It isbelieved that the non-homogenous crystalline structure is a causalfactor in the observed increase in deliquescence. As used herein, theterm “reagent grade” generally refers to a compound with the purity andquality that allows it to be used in a laboratory and the term“technical grade” generally refers to a lower purity product suitablefor commercial application. While not wanting to be bound by theory, itis believed that the byproducts produced during the process for makingthe ferric sulfate composition of the present disclosure unexpectedlyincreases the deliquescence rate once applied. Also, it has beenunexpectedly discovered that the ferric sulfate composition has improvedanti-clumping behavior due to the fact that it is less hygroscopic thanreagent grade ferric sulfate leading to improved handling as well asapplication due to its increased spreadability. Still further, theferric sulfate composition creates less dust, therefore presenting fewerhazards to the applicator and being less corrosive to adjacentstructures within the house compared to aluminum and sulfuric acid basedlitter treatment materials, which tend to produce high amounts ofundesirable dust or fog.

It was also unexpectedly discovered that with continued applications ofthe product there are indications of apparent drying of the litter inthe built-up litter house. While not wanting to be bound by theory, thismost likely is the result of utilization of the various hydration statesof the ferric sulfate composition and downstream reaction products asdiscussed in greater detail below. This manifestation of the productwill promote lower biological activity in the litter, thereby reducingbiological conversion of organic ammonia to inorganic ammonia and also,by environmental de-optimization, reduce the generation andproliferation of various undesirable microorganisms. This manifestationalso reduces the amount of caking and thereby reduces quantities oflitter for disposal in built up litter operations. A downstreamadvantage to the grower becomes the ability to maintain various drybuilt-up litter beddings which have been an indicator in the productionof quality “chicken paw” food products.

Unlike processes for preparing reagent or technical grade ferricsulfate, the present ferric sulfate composition is prepared by oxidationof ferrous sulfate with sulfuric acid using a molecular oxygen oxidizingagent at an elevated pressure relative to atmospheric and at atemperature of 60° C. to 140° C. Solidification of such slurry can beconducted advantageously by cooling, by means of a plate granulator, bymeans of a drum granulator, or by any other corresponding method. By wayof example, the resulting slurry can spheroidized in a drum granulator.A preferred process for preparing the ferric sulfate salt compositionsuitable for use in the present disclosure is described in U.S. Pat. No.5,766,566, incorporated herein by reference in its entirety.Non-homogenous partially hydrated crystals of ferric sulfate are formedin a matrix, which provides the ferric sulfate composition withrelatively with low hygroscopicity and high deliquescence. In oneembodiment, the partially hydrated ferric sulfate crystals is of theformula Fe₂(SO₄)₃·nH20, wherein n is an integer from 1 to 10. In anotherembodiment, n is an integer from 5 to 9. This unique combination ofproperties provides improved handling, spreadability, and dissolutionupon application. Moreover, it has been found that the ferric sulfatecomposition is stable under typical storage conditions and highlydeliquescent once applied. As noted above, the color of the ferricsulfate composition is gray to tan. A preferred partially hydratedferric sulfate has a substantially kornelite crystalline of the formula:Fe₂(SO₄)₃·7H₂O. By the term substantially, it is meant greater than 50percent of the total crystallinity provided in the granules.

In one embodiment, the ferric sulfate composition exhibiting theexpressed advantages has the properties as listed in Table 1 and has asubstantially kornelite crystalline of the formula: Fe₂(SO₄)₃·7H₂O. Thecolor of the product ranges from gray to tan and is generallyindistinguishable from the litter and/or bedding material, therebylowering the likelihood of inadvertent ingestion.

TABLE 1 Particle size (50%) <2-3 mm Particle size (100%) <7 mm Dust(<0.2 mm) Max 3% Appearance Gray to tan granules Total Fe (3) 19.5 ±1.0% Fe (2) ≦1.0% Free H₂SO₄ <1.5% Sulfate 54 ± 2.0% pH <2 Arsenic <0.2mg/kg Cadmium <0.1 mg/kg Calcium <0.002% Chromium <20 mg/kg Magnesium<0.4-0.8% Manganese <2300 mg/kg Mercury <0.1 mg/kg Nickel <50 mg/kg Lead<5 mg/kg Selenium <1.0 mg/kg Titanium <0.06%

The ferric sulfate composition is more effective than existing aluminumsulfuric acid and sodium bisulfate based treatments through theintrinsic oxidizing potential of the ferric or Iron III ion. Ferric orIron III ion creates a higher redox potential, and in this oxidativeenvironment, the anaerobic and facultative microorganisms that normallydrive the production of ammonia and ammonia compounds and otherpotentially deleterious microorganisms are thereby inhibited and/orreduced. This provides a significant improvement over existing littertreatments based on aluminum, sulfuric acid and sodium bisulfate that donot provide a significant inhibiting oxidative capability. Thiscapability extends the treatment effectiveness beyond existing treatmentproducts. This potentially permits fewer applications and/or lessproduct being used, requiring less labor.

Comparing the granular ferric sulfate composition to other productsavailable, (e.g., liquid alum, dry alum, sulfuric acid, reagent ortechnical grade ferrous sulfate crystals, reagent or technical gradeferric sulfate crystals, sodium bisulfate materials, and the like) theapplication of the material delivers an equal quantity or more moleculesper unit weight for reaction and therefore treatment. This alsopotentially permits longer control, requiring less labor.

It has been observed that the granular partially hydrated ferric sulfatecomposition as produced by the process described above exhibitsexcellent storage stability but more rapidly dissolves (i.e.,deliquesces faster) on application compared to other dry based materialsincluding reagent or technical grade ferric sulfate crystals andtherefore are able to protect the animals sooner with less lead time.This is especially advantageous during the brooding period of growth forpoultry facilities when the chicks are first introduced to the house andwhere environment most influences future growth rates. Table 2 providesan indication of the differences in hygroscopy between technical gradeferric sulfate (commercially obtained under the trade name Ferri-Floc)and a ferric sulfate composition (Fe₂(SO₄)₃·7H₂0) of the presentdisclosure after exposure to different levels of relative humidity aftera period of 6 days. The data for the ferric sulfate compositionrepresented an average relative humidity for two batches manufactured ondifferent days. The data shows that upon exposure to higher humidity,the absorption of water as indicated by a percent change in weight wasunexpectedly and significantly less for the ferric sulfate compositionproduced in accordance with the present disclosure than the technicalgrade ferric sulfate. In actual trial conditions it was observed thatother products based on sodium bisulfate (NaHSO₄) are very hygroscopicand tend to absorb moisture directly and quickly from the air. Thistendency can produce undesirable wet areas throughout the growingfacility, on the paper used for chicks and on the litter itself. Theferric sulfate composition in accordance with the present disclosure hasbeen found to be less hygroscopic when applied in the growing facilityeliminating the occurrences of litter and paper wetness. With the NaHSO₄products this tendency toward fast activation also puts the grower on atight schedule with respect to treatment application time and chickplacement. Additionally the production facility must be pre-heated priorto placement of the litter amendment requiring more energy. Applicationof these litter treatments is required within 24 hours to protect bothhumans and animals in the growing facility. The granular partiallyhydrated ferric sulfate composition has been found to be less criticalin this respect and generally allows up to 4 days pre-application of theproduct prior to chick placement. This provides a wider time frame forthe grower with respect to facility preparation

TABLE 2 29% 45% 55% 74% 88% Technical Grade 0.3 0.08 0.25 12.9 35.3Ferric Sulfate (Ferri-Floc) Ferric Sulfate −0.15 0.45 2.05 8.1 20.4composition

The rapidly dissolving form of the product also reduces the potentialfor direct contact of the product with the animals, the impact beingeither that the time in between growth cycles is compressed, therebyincreasing the efficiency of the grower operation, or that there isgreater ammonium reduction in the first critical days of bird growthresulting in higher growth rates and final production weight.

In one embodiment pertaining to its use in poultry production houses,the litter treatments of the ferric sulfate composition are firstapplied to the house before the first introduction of the chicks on asecond grow-out or higher litter cycle. This application of the productserves to protect the animals in their most fragile age. It is at thisstage of growth that the house is maintained at a warm temperature,which discourages the use of ventilation. It is therefore an advantagefor growers that the ferric sulfate composition permits decreasedventilation while maintaining a healthy environment for the chicksduring their first few weeks of growth. In this manner, growth rates areimproved, feed utilization rates are increased, lower heating costs arepossible due to reduced ventilation, and less exposure to handlers areprovided.

It has also been observed that the ferric sulfate composition of thepresent disclosure as applied to poultry litters provides a ‘secondwave’ of ammonia reduction in the growing facility. While not wanting tobe bound by theory, it is believed that the anaerobic environment of thelitter has a reducing effect on the ferric form of the product, takingit, in part, to its ferrous state. Additionally, with respect tospecific built up litter applications, it is believed that the chemistryand environment can oxidize the reduced iron back to the ferric state.In this context, it is theorized that the secondary ammonia uptakephenomena may be the result of secondary reactions occurring within thecomplex biological, physical and chemical environments of the litter. Anumber of available reactions exist that will sequester ammoniacompounds through the formation of various ferric and ferrous, ammoniumand sulfate complexed compounds such as Fe(NH₄)₂(SO₄)₂·6H₂O,(NH₄)₃Fe(SO₄)₃, NH₄Fe(SO₄)₂, (NH₄)₂Fe(SO₄).Fe₂(SO₄)₃·24H₂O, and othercongeners of same.

The ferric sulfate composition, as applied to the litter and/or beddingmaterial, inhibits the generation of volatilized ammonia and ammoniacompounds from poultry litter by lowering overall litter basicity andthrough the ferric ion inhibitory effect on the growth of ammoniaproducing microorganisms. Additionally, as the ferric ion is reduced toits ferrous ion state it is then available to react with ammonia andammonium ions to form iron complexes that effectively sequester theammonia and ammonium ions from further reaction potential. Thecombination of these factors extends the effective period of the productand allows the grower to apply product less frequently, approximately30-50% less often. One application per grow-out cycle is typicallyemployed in the industry. In addition to reducing ammonia emissions,treatment with the ferric sulfate composition has been found tosequester soluble phosphate compounds in the litter and/or beddingmaterial that may be present by reducing the immediate availability ofthe phosphate contained therein. Leaching of the phosphate from fieldapplied litter proceeds at a much lower rate relative to other availabletreatments and in some instances is up to 1000 times less.

The disclosure is further illustrated by the following non-limitingexample.

EXAMPLE

A four-house broiler farm was selected with houses managed asidentically as possible for ventilation, temperature, and humidity. Thehouses were 36×400 ft and stocked at a rate of 15,700 birds per house.Between flocks, the houses were opened for drying, the litter was‘decaked’ by tilling the surface, and the litter surface was top-dressedwith pine shavings. One day prior to introduction of the flock, aluminumsulfate (commercially obtained under the trade name Al+Clear® fromGeneral Chemical, Inc., and is referred to herein as Comp-1) and ferricsulfate (Fe₂(SO₄)₃·7H₂O commercially obtained under the trademarkFerix-3® from Kemira, and is referred to herein as Inv-1) were appliedat a rate of 22.7 kg per 92.9 m² (100 lbs per 1000 ft²) to the littersurface in each of two houses. Comp-1 was applied in houses 1 and 2, andInv-1 was applied in houses 3 and 4.

Both Comp-1 and Inv-1 litter amendments were applied at the same timeand at the same rate of 22.7 kg per 92.9 m² (100 lbs per 1000 ft²) justprior to bird placement. No other application of either litter amendmentwas made throughout the remainder of the flock cycle. Litter sampleswere taken prior to application and on day-of-study (DOS) 4, 6, 8, 13,20, 27, and 36. Analyses of the litter samples included organic N (ON),NH₄ ⁺, nitrate N (NO₃ ⁻), total N (N), calcium (Ca), copper (Cu), iron(Fe), magnesium, (Mg), manganese (Mn), P, potassium, (K), sodium (Na),sulfur (S), and zinc (Zn). Other analyses included percent moisture, pH,dry matter content, and soluble salts.

House environmental data collection included air temperature, fan flowrate, and aerial ammonia concentration. Ammonia concentrations weremeasured using two techniques:

-   -   1. Dosimeter passive absorption tubes (Gastec, Inc.) were        attached at one-meter height in all four houses at locations ¼,        ½, and ¾ distance from the air-intake end of the house. They        were installed during the prescribed data-collection days (DOS)        2, 4, 6, 8, 13, 20, 27, and 36 and remained in the houses for 6        to 12 hours.    -   2. A gas-washing technique was used to obtain ammonia        concentrations by drawing unfiltered air through gas-washing        bottles containing 180 mL of 0.2 N sulfuric acid at a known flow        rate (2 L/min).

At the end of the sample period the gas-washing bottles were removed,capped, and taken to a laboratory for extraction into 90 mL glassstorage bottles. The samples were refrigerated until analysis bystandard colorimetric techniques. The resulting aerial concentrationswere converted from a weight-per-volume basis (μg/m⁻³) to a volume-basis(ppm) through the use of the gas-law equation. The average seasonalaccuracy for the technique was 0.020 ppm ammonia-N. All ammoniaconcentrations were normalized with respect to the fan-flow rate ofhouse 1 by linear ratio to the other individual house fan-flow periods.Additional data obtained from the host organization included fan-flowrates, house temperature, feed conversion efficiency, and carcassquality.

With respect to the treatments, a considerable amount of dust wasgenerated during the application of the Comp-1 (i.e., aluminum sulfate)treatment compared to the Inv-1 (i.e., ferric sulfate composition)treatment, requiring the applicator to use a facemask during the Comp-1application but not so during the Inv-1 application. The difference indust levels was qualitatively observed.

FIGS. 1 and 2 graphically illustrated ammonia concentrations. Houses 2and 3 were the houses instrumented with gas-washing techniques toaccurately establish interior and exterior ammonia concentration (20 ppbfor this study). All four houses were instrumented (interior only) withdosimeter tubes (accuracy estimated at a few parts per million (ppm))for comparison with the gas-washing concentrations. As expected, bothmeasurement techniques showed that ammonia concentrations were lowestafter application for both litter treatments (lower in the Inv-1 houses)and increased as the flock aged. Comparing ammonia concentrations inhouses 1 and 4 using the dosimeter measurements (FIG. 1B) indicated thatthe Inv-1 treatment in house 4 was more effective at controlling ammoniathan that in the Comp-1 treatment in house 1. The dosimeter tubes showedthere was no difference between houses 2 and 3 (FIG. 1B), due likely toexcessive litter moisture during the study (FIG. 1C). The averages ofboth Inv-1 and Comp-1 houses indicate that Inv-1 was more effective forthe first 15 days (FIG. 1A). Houses 2 and 3 measurements usingmore-accurate gas washing ammonia techniques, showed also that the Inv-1house 3 was more effective at controlling ammonia during the first 7days (FIG. 2A). After 7 days, the Inv-1 house 3 was less effective thanthe Comp-1 house 2 because the litter moisture in the Inv-1 house 3 wasmuch higher (FIG. 2D).

After the first few days, the house temperatures were graduallydecreased from a set temperature of 31° C. (by reducing heat input andincreasing ventilation) to a final set temperature of 24° C. (about DOS23). After DOS 10, ambient temperatures increased considerably andventilation rates were ramped up to reduce interior heat buildup andammonia concentrations (FIG. 2D).

Litter analyses showed that the Inv-1 treatment significantly retainedmore nitrate nitrogen in the litter (FIGS. 3A through D) than the Comp-1treatment. Organic nitrogen and total nitrogen were retainedsignificantly (one Standard Error) larger in the Inv-1 houses until thelast two weeks of the study where the absolute amounts were numericallybut not significantly larger. Ammonium nitrogen was not significantlydifferent between the treatments throughout the study period. Theseresults suggest that housing and management characteristics removedammonia from the litter about the same for both treatments but the Inv-1treatment retained nitrogen in the litter in all other forms by reducingmineralization of organic nitrogen, uric acid, and other forms ofnitrogen. It also suggests accelerated nitrification of ammonium tonitrate as a form of nitrogen retention by the Inv-1 treatment.

Ammonia is also controlled by increasing the hydrogen ion concentration(lower pH) in the litter. There was no significant difference in litterpH between the two treatments at the 100 lb laydown level (FIG. 3E).

Iron was higher in the Inv-1 houses, as anticipated, because of thetreatment application, as well as calcium, magnesium, manganese, sulfur,and zinc (FIGS. 4A-F). There was no difference in copper, phosphorous,potassium, sodium, or soluble salts between treatments (FIGS. 5A-E).

There was no significant difference in mortality between treatments.Bird performance was not affected by the litter treatments though birdweights were slightly higher in the Comp-1 houses than in the Inv-1houses (6.39 vs. 6.29, respectively). The results of this study suggestthere are no differences in animal performance between the two littertreatments. This lack of difference is to be expected as each house wasmanaged with a sufficient rate of air exchange to create an environmentfor optimal bird performance.

The Inv-1 treatment was, on average, superior to the Comp-1 treatment inreducing ammonia concentrations in the houses during the first 15 daysafter chick placement, despite wet litter conditions in two of the fourhouses. During the critical brooding period, the two treatmentsfunctioned equally well with regard to bird survivability andperformance. The Inv-1 treatment did show significant retention ofnitrogen in the litter over the Comp-1 treatment. This example shows theapplication of ferric sulfate in the granular, rapidly dissolving formof this example has advantages as a poultry litter treatment for ammoniacontrol in commercial poultry production facilities.

Advantageously, the use of the ferric sulfate composition as describedabove is less risk to workers, it is more active per unit weight thantypical litter and/or bedding material treatments, it becomes activemore quickly in lowering pH of litter, and it provides a redoxenvironment more inhibitory to ammonia producing microorganisms.Moreover, the ferric sulfate can be used for reduction of hydrogensulfide emissions. Suitable applications include, but are not limitedto, other animal manures, landfills, and the like.

In another embodiment, ferric ion also binds phosphorous moreeffectively than typical aluminum based litter treatments, potentiallylowering phosphorous run-off on land-applied litter.

Although the example has been made to poultry, those of skill in the artwill appreciate in view of this disclosure that the ferric sulfatecomposition of the present disclosure a composition can be used in othertypes of applications where it may be desirable to de-volatilizeammonia, reduce soluble phosphorous levels, and the like.Advantageously, in addition to lowering ammonia and sequesteringphosphates, the use of the litter amendment serves to lower energyrequirement as it relates to ventilation requirements due to the reduceammonia emissions and thus, will add measurable value to the operation.

For example, the ferric sulfate composition can be applied for treatmentof various animal based manures, landfills, and the like. This includes,but is not limited to, equine, dairy cattle and/or calves, and swineapplications.

The singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise. All references are incorporatedherein by reference.

While the disclosure has been described, it will be understood by thoseskilled in the art that various changes can be made and equivalents canbe substituted for elements thereof without departing from the scope ofthe invention. In addition, many modifications can be made to adapt aparticular situation or material to the teachings of the inventionwithout departing from the essential scope thereof. Therefore, it isintended that the invention not be limited to the particular embodimentdisclosed as the best mode contemplated for carrying out this invention,but that the invention will include all embodiments falling within thescope of the appended claims.

What is claimed is:
 1. A method of treating animal litter and/or beddingmaterial comprising: applying a granular form of a partially hydratedferric sulfate composition to the animal litter and/or bedding materialprior to a use of the animal litter and/or bedding material by ananimal; and introducing the animal to the animal litter and/or beddingmaterial.
 2. The method of claim 1, further comprising: reapplying thepartially hydrated ferric sulfate composition to the animal litterand/or bedding material, wherein the reapplied partially hydrated ferricsulfate composition dries the animal litter and/or bedding material. 3.The method of claim 1, further comprising: reducing ammonia emissionsfrom the animal litter and/or bedding material after introduction of theanimal as compared to animal litter and/or bedding material not havingany partially hydrated ferric sulfate composition; and reducing solublephosphorous levels from the animal litter and/or bedding material afterintroduction of the animal as compared to animal litter and/or beddingmaterial not having any partially hydrated ferric sulfate composition.4. The method of claim 1, wherein the partially hydrated ferric sulfatehas a formula of Fe₂(SO₄)₃·nH₂O, wherein n is an integer from 1 to 10.5. The method of claim 1, wherein the partially hydrated ferric sulfatehas a formula of Fe₂(SO₄)₃·nH₂O, wherein n is an integer from 5 to
 9. 6.The method of claim 1, wherein the partially hydrated ferric sulfate hasa formula of Fe₂(SO₄)₃·7H₂O.
 7. The method of claim 1, wherein theanimal is poultry.
 8. The method of claim 1, wherein the animal isswine.
 9. The method of claim 1, wherein the animal is equine.
 10. Themethod of claim 1, wherein the animal litter and/or bedding material isfrom dairy cattle and/or calves.
 11. The method of claim 1, furthercomprising: maintaining the animal litter and/or bedding material at apH less than 7.5.
 12. The method of claim 1, wherein at least 90 percentof the partially hydrated ferric sulfate has a particle size greaterthan 0.2 millimeters and at least 50 percent of the ferric sulfate hasparticle size greater than 1 millimeter.
 13. The method of claim 1,further comprising: applying the partially hydrated ferric sulfatecomposition at a coverage rate effective to reduce ammonia emissions andreduce soluble phosphorous levels as compared to animal litter and/orbedding material not having any partially hydrated ferric sulfatecomposition.
 14. The method of claim 1, wherein the ferric sulfate isprepared by a process comprising oxidizing ferrous sulfate with sulfuricacid using a molecular oxygen oxidizing agent at an elevated pressurerelative to atmospheric and at a temperature of 60° C. to 140° C. toproduce a slurry, and drying the slurry to produce a gray to tan coloredgranular product.
 15. The method of claim 1, wherein the ferric sulfatehas a substantially kornelite crystalline structure.
 16. A method oftreating animal litter and/or bedding material comprising: applying agranular form of a partially hydrated ferric sulfate composition to theanimal litter and/or bedding material prior to a use of the animallitter and/or bedding material by an animal; introducing the animal tothe animal litter and/or bedding material; reducing ammonia emissionsfrom the animal litter and/or bedding material prior after introductionof the animal as compared to animal litter and/or bedding material nothaving any partially hydrated ferric sulfate composition; reducingsoluble phosphorous levels from the animal litter and/or beddingmaterial prior after introduction of the animal as compared to animallitter and/or bedding material not having any partially hydrated ferricsulfate composition; reapplying the partially hydrated ferric sulfatecomposition to the animal litter and/or bedding material, wherein thereapplied partially hydrated ferric sulfate composition dries the animallitter and/or bedding material; and maintaining the animal litter and/orbedding material at a pH less than 7.5.
 17. The method of claim 16,wherein the partially hydrated ferric sulfate has a formula ofFe₂(SO₄)₃·7H₂O.
 18. The method of claim 17, wherein the ferric sulfatehas a substantially kornelite crystalline structure.
 19. The method ofclaim 16, wherein the animal is poultry.
 20. The method of claim 16,wherein the animal is swine.
 21. The method of claim 16, wherein theanimal is equine.
 22. A method of treating animal litter and/or beddingmaterial comprising: applying a granular form of a partially hydratedferric sulfate composition to the animal litter and/or bedding material.23. The method of claim 22, wherein when an animal is introduced to theanimal litter and/or bedding material: ammonia emissions from the animallitter and/or bedding material are reduced as compared to animal litterand/or bedding material not having any partially hydrated ferric sulfatecomposition; and soluble phosphorous levels from the animal litterand/or bedding material are reduced as compared to animal litter and/orbedding material not having any partially hydrated ferric sulfatecomposition.
 24. The method of claim 23, further comprising: reapplyingthe partially hydrated ferric sulfate composition to the animal litterand/or bedding material, wherein the reapplied partially hydrated ferricsulfate composition dries the animal litter and/or bedding material. 25.The method of claim 24, further comprising: maintaining the animallitter and/or bedding material at a pH less than 7.5.